feat(mcp): add SSE (Server-Sent Events) transport type support

Add comprehensive support for SSE transport type to MCP server configuration,
enabling real-time streaming connections alongside existing stdio and http types.

Backend Changes:
- Add SSE type validation in mcp.rs validate_server_spec()
- Extend Codex TOML import/export to handle SSE servers
- Update claude_mcp.rs legacy API for backward compatibility
- Unify http/sse handling in json_server_to_toml_table()

Frontend Changes:
- Extend McpServerSpec type definition to include "sse"
- Add SSE radio button to configuration wizard UI
- Update wizard form logic to handle SSE url and headers
- Add SSE validation in McpFormModal submission

Validation & Error Handling:
- Add SSE support in useMcpValidation hook (TOML/JSON)
- Extend tomlUtils normalizeServerConfig for SSE parsing
- Update Zod schemas (common.ts, mcp.ts) with SSE enum
- Add SSE error message mapping in errorUtils

Internationalization:
- Add "typeSse" translations (zh: "sse", en: "sse")

Tests:
- Add SSE validation test cases in useMcpValidation.test.tsx

SSE Configuration Format:
{
  "type": "sse",
  "url": "https://api.example.com/sse",
  "headers": { "Authorization": "Bearer token" }
}

src/lib/schemas/common.ts

@@ -58,7 +58,7 @@ export const jsonConfigSchema = z
  * 通用的 TOML 配置文本校验：
  * - 允许为空（由上层业务决定是否必填）
  * - 语法与结构有效
- * - 针对 stdio/http 的必填字段（command/url）进行提示
+ * - 针对 stdio/http/sse 的必填字段（command/url）进行提示
  */
 export const tomlConfigSchema = z.string().superRefine((value, ctx) => {
   const err = validateToml(value);
@@ -80,10 +80,13 @@ export const tomlConfigSchema = z.string().superRefine((value, ctx) => {
         message: "stdio 类型需填写 command",
       });
     }
-    if (server.type === "http" && !server.url?.trim()) {
+    if (
+      (server.type === "http" || server.type === "sse") &&
+      !server.url?.trim()
+    ) {
       ctx.addIssue({
         code: z.ZodIssueCode.custom,
-        message: "http 类型需填写 url",
+        message: `${server.type} 类型需填写 url`,
       });
     }
   } catch (e: any) {

src/lib/schemas/mcp.ts

@@ -2,7 +2,7 @@ import { z } from "zod";
 
 const mcpServerSpecSchema = z
   .object({
-    type: z.enum(["stdio", "http"]).optional(),
+    type: z.enum(["stdio", "http", "sse"]).optional(),
     command: z.string().trim().optional(),
     args: z.array(z.string()).optional(),
     env: z.record(z.string(), z.string()).optional(),
@@ -19,10 +19,10 @@ const mcpServerSpecSchema = z
         path: ["command"],
       });
     }
-    if (type === "http" && !server.url?.trim()) {
+    if ((type === "http" || type === "sse") && !server.url?.trim()) {
       ctx.addIssue({
         code: z.ZodIssueCode.custom,
-        message: "http 类型需填写 url",
+        message: `${type} 类型需填写 url`,
         path: ["url"],
       });
     }